I think stat function can be used to know actual permissions. is_* function supposed to return if current process can do something or not. IMO.

We may need to change doc a bit. -> Documentation Problem

In the current release of the manual is_readable/is_writable now mention the fact that they will not check safe_mode limitation. The is_executable however, still needs to be documented.

I recently ran into this same problem.  With the open_basedir config option set, is_readable() can report unexpected results.

Perhaps a solution may be to run through all of the security checks that fopen goes through and find out if the file is readable.  Another solution would be to actually just flat out open the file with php_fopen() for read or append (for is_writable()) and see what is returned.

Perhaps an argument can be added such as:

is_readable(STRICT) where STRICT checks everything

is_readable(STRICT | ATTEMPT) would actually attempt the open.

I'm just throwing out ideas.  My problem is that I would like a way to guarantee that no errors or warnings are returned by a call to fopen() with the E_ALL error level set.  I was using:

file_exists() && is_readable()

I can't think of any check to perform other than writing a function in my script that does a "safe" open such as:

function is_truly_readable()
{
  $e = error_reporting(0);
  if ($f = fopen($file, "r"))
  {
    fclose($f);
    error_reporting($e);
    return(TRUE);
  }
  error_reporting($e);
  return(FALSE);
}

Safe mode was gone.